1 - FUNCTIONAL ANATOMY OF Tx & RIB CAGE

Question 1

Thoracic vertebrae: description

Answer 1

12 thoracic vertebrae, T1 to T12

• Each vertebra has body (corpus), vertebral foramen, spinous process, transverse process & articular facets.
  Spinous processes = long & angled downward, especially in mid thoracic region (T5-T8)
• Reach vertebra has costal facets (demi-facets) on vertebral body for head of rib &
  transverse costal facet on transverse process for tubercle of rib (T1-T10)

Question 2

Thoracic disc: description

Answer 2

Disc height to vertebral body height ratio (1/5) (1/3 in Lx & 2/5 in Cx)

Thoracic disc abnormalities in asymptomatic individuals:
- 37% thoracic disc herniations
- 53% disc bulging
- 58% annular tears
- 29% spinal cord deformity

Question 3

Rib cage

Answer 3

• Sternum: manubrium, body & xiphoid process
• 12 pairs of ribs:
  o True ribs (1-7): attach directly to sternum via own costal cartilage
  o False ribs (8-10): attach indirectly vie cartilage of rib above
  o Floating ribs (11-12): have no anterior attachment

Question 4

Ribs: typical & atypical

Answer 4

Typical ribs (ribs 3 to 9)
- Head = 2 articular facets
o Superior facet → articulates with vertebra above
o Inferior facet → articulates with same numbered vertebra
- Neck
- Tubercle = facet articulating with transverse process of same-numbered vertebra
- Shaft = provides attachment for inter-costal muscle
- Costal angle
- Costal groove = on internal inferior border. Protects inter-costal vein, artery & nerve (VAN)

Atypical ribs
- Rib 1: broad, flat & shortest rib. Only one articular facet on head (articulates with T1 only). No costal groove. Superior surface has grooves for: subclavian vein & artery. Has scalene tubercle (attachment for
anterior scalene)
- Rib 2: rough area on upper surface for serratus anterior attachment. Head has 2 facets (like typical ribs)
- Rib 10: only one facet on head (articulates with T10 only)
- Rib 11 & 12: no tubercle. Only one facet on head (T11 or T12). Do not articulate anteriorly (no costal
cartilage connection)

Question 5

Thoracolumbar transition

Answer 5

Thoracolumbar transition (T10-L2)
Shift from thoracic kyphosis to lumbar lordosis:
- T12: transition point in 22% of individuals
- L1: transition point in 33% of individuals
- L2: transition point in 21% of individuals

Question 6

Kyphosis

Answer 6

Kyphosis
- Normal angle = 45° (range 20°-70°) in asymptomatic spines
- Increases with age due to progressive fibrosis of posterior muscles
- Leads to hyper kyphosis in older adults
- Apex of kyphosis usually at T6
- Apex location independent of age & sex

Question 7

Muscle posterior thorax

Answer 7

• erector spinae group
• semispinalis
• multifidus

Table

Question 8

Respiratory muscle

Answer 8

Table

Question 9

Thoracic spine in motion: biomecha
- facet joint orientation & mobility

Answer 9

Facet joint orientation & mobility
- Facets oriented in frontal plane (around 60°) → limits flexion / extension, allows axial rotation
- Main movement: axial rotation (T1-T10)
- Lower thoracic (T11-T12): more sagittal orientation → increased flexion / extension
- Rib cage restricts motion, especially flexion & side bending

Question 10

Thoracic spine in motion: biomecha
- costal facet joint orientation & mobility

Answer 10

• Upper ribs (1-5): pump handle movement → increased anteroposterior diameter
• Middle ribs (6-10): bucket handle movement → increased transverse diameter
• Lower ribs (11-12): Caliper movement → lateral expansion
• Mobility depends on costovertebral joints, thoracic spine & soft tissues
• Dysfunctions may include reduced rib motion, asymmetry, increased accessory breathing

Question 11

Thoracic spine in motion: biomecha
- coupling of rotation & side bending + influencing factors

Answer 11

• In upper thoracic spine (C7-T2): side bending & rotation occur to same side
• In mid thoracic spine (T3-T7): coupling is variable
• In lower thoracic spine (T8-T12): coupling often contralateral, especially at end range movements

Influencing factors:
- Rib orientation & costotransverse joint alignment
- individual anatomy & movement direction
- Spinal posture (neutral vs flexion/extension)

Question 12

Steps of assessment thoracic dysfunction

Answer 12

Observation
Global mobility
Regional mobility
Segmental mobility

Question 13

Observation of thoracic dysfunction

Answer 13

Image

Question 14

Global mobility

Answer 14

Image

Question 15

Regional mobility

Answer 15

Image

Question 16

Segmental mobility

Answer 16

Table